With Samuel and Rose, definitely Elisabeth of the three - it's a more of a timeless classic like your other children's names. Not that big a deal to have to say "Elisabeth with a S" if that spelling will reflect her heritage (with a Z would be the UK assumption).
Second choice would be Hazel as it shares the botanical theme with Rose, but has the same ending as Samuel, so sounds nice as a sibset if that matters . But it is much less timeless - Hazel is coming back into fashion now, but it was previously fairly 50's/60's. Equally Melissa feels a bit dated to the 80'/90's.